In the past, modular floating docks have been created by the assembly of a number of floating subunits. These subunits include various geometric shapes with planar upper and lower surfaces. The subunits connect together to create flexible docks and walkways having various shapes and sizes based on the consumers needs.
For example, U.S. Pat. Nos. 3,824,644 and 4,604,962 disclose a substantially prismatic, floating element having rounded corner edges. The elements are provided with outwardly projecting eye lugs for flexible attachment to adjacent elements.
U.S. Pat. No. 4,655,156 discloses a stackable floating element. The elements include alternating rectangular projections and cavities for interlocking the elements in a stacked arrangement. The stacked arrangements are secured together via tabs and bolts to create a flexible assembly.
U.S. Pat. No. 5,251,560 discloses a water-float coupling device for coupling together hexagonally shaped floats having planar upper and lower surfaces. The device extends through a plurality of stacked outwardly extending tabs for flexible connection between the units.
U.S. Pat. No. 6,033,151 discloses a float unit having planar upper and lower surfaces and corrugated side surfaces. The corrugated side surfaces engage with adjacent floats to provide friction between the units. The units are secured together by extending a bolt through stacked tabs which extend outwardly from the corners of each float unit.
U.S. Pat. Nos. 6,138,599 and 5,947,049 disclose a buoyant walkway module for a boatlift. The device includes a plurality of elongated compartments having planar top and bottom surfaces. The device also includes planar ends for connecting the walkways together in an end to end relationship.
U.S. Pat. Nos. 6,073,572 and 6,179,525 disclose floating dock sections. The sections are interlocked via a number of flanges to create decks or walkways.
U.S. Pat. No. 6,138,600 discloses a hollow float that includes a hollow inner cavity and a plurality of open cavities that extend upward from the bottom surface of the float.
U.S. Pat. No. 5,875,727 discloses a floating lift for docking a personal watercraft from a body of water. The float includes a shell filled with a buoyant filler. A replaceable skid plate is centered on one end of the shell to engage the bow of a watercraft during docking. The shell includes two pairs of posts, one pair extending forwardly from the front of the shell and the other extending rearward from the rear of the float. A flat elastic member is used to extend between posts of adjacent shells to flexibly connect the shells together.
These prior art devices work relatively well for constructing flexible walkways and platforms. However, these devices have numerous shortcomings. The size of the floatation units and the flexible connection between the units causes the units to closely follow the contour of the water. This construction also causes instability and makes the units difficult to walk along. When weight is applied to small individual units they displace downwardly, when the weight is removed the floats follow the load upward. This action gives an individual a similar sensation to walking on a rope bridge.
It is also known in the prior art to construct floating flexible or pivotable drive-on type docks. The docks are assembled from floating elements having various geometric shapes to create a dock which allows a boat operator to drive his/her watercraft directly onto the upper surface of the dock using the boats power. As the watercraft is driven onto the dock the floating elements typically flex or pivot downward to a position below the water-line until a sufficient amount of floatation devices are beneath the watercraft to raise it above the water line.
For example, U.S. Pat. No. 3,977,030 discloses a metal frame upon which buoyancy elements are rotatably and pivotably mounted.
U.S. Pat. Nos. 5,529,013 5,682,833, and 5,947,050 disclose a floating dry dock consisting of two arms constructed from short and tall cubical floatation units having an open well in the middle portion thereof. The floatation units having the least buoyancy are secured at the distal ends of the arms for downward pivotal movement under the water surface during boat docking.
U.S. Pat. No. 5,941,660, issued to the instant inventor, teaches a watercraft support structure formed from a plurality of platforms that are coupled together by linking pins or insertion plugs for a limited amount of pivotal movement during docking.
U.S. Pat. Nos. 3,951,087 and 6,602,022 disclose apparatus for lifting and storing a boat above the water in the well of a dock or floating dry dock. The device includes a metal frame onto which the boat may be driven. The frame is pivotally mounted within the open well such that the frame can be tilted downward when loading the boat and thereafter be pivoted to a level position.
While these designs are functional, they have numerous shortcomings that have not been addressed in the art. For example, in order to provide guidance for the boat hull when used for drive-on docking, the planer surfaced flotation units must be spaced apart leaving an open well between the two arms. This construction provides a poor guiding surface for most boat hull constructions. In addition, the narrow width of the floatation units and the flexible connections associated therewith make these structures extremely unstable for pedestrian traffic and unsuitable for decks or walkways. This safety hazard is magnified when the docks are used at night or in rough waters.
Still further, the open wells within these dock assemblies combined with the wave action associated with large bodies of water often results in repeated splashing of water into the drive units of the docked watercraft and thus causes premature failure of important components of the watercraft drive system. Keeping a watercraft high and dry when not in use is important to protecting the machinery of the craft. This is particularly true of jet type propulsion systems and is critical when the craft is docked in salt water.
Other floating drive-on docks of the prior art are constructed to be lowered below the water-line with ballast for loading a watercraft. These float units are typically filled with water until the watercraft has been loaded. Thereafter, the water ballast is forced from floatation units with air to raise the watercraft above the surface of the water. As described above, the floatation units are generally cubical with tabs projecting from the vertical edges at or near the horizontal midline for flexible attachment to adjacent units. Alternatively the floating units may be supplied in the form of pontoons or other hollow structures which may alternately be filled with water and air. For example, U.S. Pat. Nos. 2,894,472, 4,018,179, 4,510,877, 5,931,113 and 6,745,714 show similarly constructed devices.
In addition to the shortcomings described above, the air systems utilized within these devices are complex and significantly increase the initial cost of the dock. In addition, cost of maintaining the air and water pumps in a marine environment is increased, while reliability of the systems is decreased.
Thus, what is needed in the art is a connecting link assembly and socket arrangement for assembling modular dock elements into walkways, decks and drive-on docks to provide increased versatility and safety. The connecting link and the connecting link socket should have conjugate profiles that are easily molded from polymeric materials and methods well known in the art. The connecting link assembly and socket arrangement should cooperate in such a manner to allow substantially rigid drive-on docks and decks to be easily and quickly assembled with a minimum number of tools. The structural floating elements should provide a surface which allows a watercraft to slide easily for drive-on docking without hull damage, while providing superior grip for pedestrian traffic. The structural elements may be constructed with like or dissimilar buoyancies for increased assembly versatility. Structural floating elements should also provide a guiding surface for boat hulls when being driven onto the dock. The guiding surfaces should be provided without dangerous open wells.